Pros: Highly effective, I didn't measure it but I would certainly believe than it can move 12 gallons a day. Easy to refill, Wicks are inexpensive. Cons: Noisy, poor quality, creates a draft of cold air.
This product comes from Essick Air, and it is cheaply constructed (judging from other reviews, such is the quality standard of all their products). This item must have a huge profit margin because it is little more than some flimsy plastic parts which don't fit together very well, plus an electric fan. Everyone seems to have different quality issues; on my unit, the float sensor is nonfunctional (either always on or always off, depending on how you adjust it). The hydrostat seems to be calibrated way off -- it reads about 10-15% lower than my (calibration verified) Caliber III Thermometer Hygrometer -- but still works, as long as you set it high enough.
But the main problem with this humidifier is the noise. On low it is loud enough to hear from 25 feet away. On medium it is hard to have a conversation. On high it drowns out most other noise. My girlfriend had to turn up the TV over it even when on low. On top of the fan noise, the propeller seems to be not quite balanced, so that the whole thing vibrates, and even rattles if oriented wrong.
Unfortunately for us consumers (but fortunately for Essick Air), there seems to be a few options for in-house humidifiers on the market with more than a few gallons a day of output. So if you really need all 12 gallons/day, and can't get one integrated with your heating system, this might be the best product on the market, despite all its shortcomings.